SparkFun Forums

[paulle]

I am new to Arduino and have a question. My project is to automate to lift open the window blind. I am thinking the board will control a motor which will roll up the blind, but I am getting stucked of how to stop the motor when the blind is lift to the top of the window. Any idea is appreciated.

[jremington]

http://en.wikipedia.org/wiki/Limit_switch

[paulle]

Is it possible to calculate number revolutions from the time of starting the motor? or another word is to get feedback from the motor of how many revolution it has gone through

[Mee_n_Mac]

Is it possible to calculate number revolutions from the time of starting the motor?

Yes and you'd be better off using a stepper motor in that case. But I'd still recommend a switch of some sort. I would also recommend a current monitor, as every blind I've ever used has gotten bound up as some point. Unless you have some clutch mechanism btw the motor and drive, you might overheat the motor. If the current monitor indicates too much motor current for too long, it's time to shut off the motor. You might also use it in place of a limit switch.